1. Field of the Invention
This invention concerns blood pressure measurements of the sort involving the application of an occluding cuff to an extremity of the subject in which the blood pressure measurement is to be performed and more particularly concerns apparatus for automatically accomplishing such cuff application.
2. Description of the Prior Art
Due to the widespread incidence of blood pressure abnormalities, particularly high blood pressure, in the population at large and due to the insidious onset of such abnormalities and their potentially highly destructive effects on the health of the afflicted individual, it has been heretofore seen as highly desirable that some mass screening system should be devised so as to enable regular and widespread monitoring of the blood pressure conditions of members of the populace. Automation of the testing procedure has been seen as desirable since traditional clinical methods of performing such measurements involve substantial time expenditure by skilled personnel such as doctors, nurses and other clinicians. The performance of such blood pressure measurements involve a fairly sophisticated technique of inflating an occluding pressure cuff encircling an extremity of the subject, usually the upper arm, with a stethoscope used to listen to the blood flow in the arteries downstream of the occluding pressure cuff. The pressure cuff is initially inflated sufficiently to totally block blood flow to the extremity remote from the point of application of the cuff, and the cuff pressure is subsequently allowed to decline gradually to a point wherein unrestricted blood flow can occur. The clinician by utilizing the stethoscope is able to detect certain characteristic sounds (referred to as "Korotkoff sounds") occurring at cuff pressures corresponding to systolic and diastolic pressure points, in order to determine these pressure values.
Many efforts have been exerted to automate the detection of such systolic and diastolic pressure points in conjunction with an inflatable cuff of the type described. Copending Patent application Ser. No. 714,097, filed Aug. 13, 1976, discloses one such arrangement.
One aspect of such automated methods is that the data so obtained must correspond to the body of clinical data which has been assembled in the past in the carrying out of traditional measurements since such clinical data forms the basis for detection of abnormalities.
Incidental to such automated processes, it would be desirable that the application of the cuff be automated as is the systolic-diastolic pressure point detection function. Most desirably, in carrying out the tests, the subject would merely have to position his wrist, arm, etc., within an opening and the occluding pressure cuff would be automatically applied and pressurized in order to carry out the blood pressure measurement, in the interests of speed and accuracy.
As mentioned above the automation of the process would most desirably closely resemble the procedure carried out in traditionally making such blood pressure measurement.
An example of a prior art automatic applicator is found in U.S. Pat. No. 3,935,984 which shows a cuff applicator in which an encircling flexible band is provided with an inflatable chamber disposed within the band over a portion of its interior. The band is adapted to be automatically reduced in diameter by virtue of a cable adapted to force a free end of the band into overlapping relationship with itself to reduce the opening into which the subject's arm has been placed until the inflatable chamber is brought into firm engagement with the subjects arm and the encircling band has occluded blood flow through the arm of the subject. Since the pressure surges within the inflatable chamber are produced by an engagement between the arm of the subject and the inflatable chamber, and since this differs from that existing between an inflatable cuff entirely encircling the arm as in traditional methods, some variations between readings obtained based on such cuff pressure readings and the traditional clinical data could occur.
It is therefore an object of the present invention to provide an automatic applicator arrangement for such blood pressure measurement cuff which resembles closely the situation existing in traditional blood pressure measurement procedures.